DropElementWdg Issue - Tactic 4.9

[piplinecamel]

Hello,

the DropElementWdg does not work for us in Tactic 4.9.
If we have the Accepted Drop Type: restriction on, the element can not be dropped into the DropElementWdg column. The issue says that the asset type is not correct. But the element is part of the allowed Drop Type. 
When we don't have the restriction on, every element can be inserted, but nothing can be saved. The filled column will be empty after saving. 

We updated our project recently from 4.4 to 4.9. The DropElementWdg is used for a planer in a vfx template style project and worked in 4.4 fine. 
The view shows two sides, with two sTpyes. Both sTypes are also connected with an container vfx. Both base sTypes include the assets they should, and the container can be filled by using the csv import.

The XML code of the asset drop column looks like this:

<element name="asset_drop" width="191px" edit="false">
  <display class="tactic.ui.table.DropElementWdg">
    <accepted_drop_type>vfx/asset</accepted_drop_type>
    <instance_type>vfx/asset_in_shot</instance_type>
    <display_expr>@GET(vfx/asset.name)</display_expr>
    <css_background-color>#425952</css_background-color>
  </display>
  <action class="tactic.ui.table.DropElementAction">
    <instance_type>vfx/asset_in_shot</instance_type>
  </action>
</element>

The whole behavior looks similar to a bug from earlier Tactic versions, where saving the column definition could delete the action class section from the definition. But:

Code:

<action class="tactic.ui.table.DropElementAction">
    <instance_type>vfx/asset_in_shot</instance_type>
  </action>

stays in the definition.

Did anyone know if this Widget doesn't work anymore or if we missed something.
The code for drop_element_wdg is also there src/tactic/ui/table/drop_element_wdg.py

Thank you very much in advance.

[remkonoteboom]

Really sorry, this has been a really busy week. We'll get somebody to take a look at this.